Wheelchair

ABSTRACT

A seat support for a wheelchair, with a telescopically-joined support column and seat column for connecting to a cushioned seat, in which support pins in the support column are set for positioning the seat column at a selected height and a latch plate operatively and selectively detachable for securing the seat column to the pins. The support column connects to a land portion of a wheelchair chassis which also connects to drive wheels.

The present application is a divisional of application Ser. No.08/685,412, filed Jul. 23, 1996, issued Mar. 23, 1999, as U.S. Pat. No.5,884,928.

TECHNICAL FIELD

The present invention relates to wheelchairs. More particularly, thepresent invention relates to wheelchairs and chassis that are moreeasily assembled, disassembled, adjusted, and used for mobility ofdisabled persons.

BACKGROUND OF THE INVENTION

Conventional wheelchairs provide equipment for use by disabled personsin order to be mobile and to increase the opportunities of disabledpersons to participate more fully in daily activities. Conventionalwheelchairs are typically manufactured of metal tubes which are cut tolength, bent into shape, and welded together to form a tubular framethat supports a seat and back. Wheels connected to the frame providemobility. Push handles attach to the back of the frame for pushing thewheelchair or controlling its direction of the movement. The purpose ofwheelchairs is to provide equipment which solves disability-relatedproblems, so that disabled persons can more easily participate ineveryday life activities while minimizing the problems created by theequipment.

Generally, wheelchairs for profoundly immobilized persons arecustom-built using specific measurements of the particular person to usethe wheelchair. The measurements are used to determine the particularwidth, depth, and height of the frame, the seat, and the seat back forthe wheelchair. Generally, wheelchairs are manufactured in widthsranging from 10 inches to 20 inches, and depths ranging from 12 inchesto 18 inches, with varying seat and back heights. Because of the manycombinations of sizes, it is expensive to maintain inventories ofspecific sized component parts. Accordingly, manufacturers ofwheelchairs cut elongated tubular members to size based on a customizedspecification for the particular individual. The tubes are assembledinto a frame of a specific design. Production of an individualwheelchair is complex and slowed because custom parts have to bemanufactured. Also, due to personalized customization of the dimensionsof a wheelchair, it is not practical to maintain inventories ofcompleted frames. Similarly, the large number of variations andcombinations prevent retailers of wheelchairs from holding wheelchairsin inventory. Further, there often is a lag time of many weeks betweenordering a custom wheelchair and delivery of the wheelchair to the user.

During manufacture, the frame members are typically joined together bywelding. The seats, backs, pads, push handles and wheels are thenconventionally connected to the frame using clamps, tubular connectors,latches, and bolts with nuts. While these secure the components to theframe, the connectors must be loosened, removed, and re-positioned foradjusting the orientation and position of the components. For aides towheelchair users who are not skilled in mechanics, operation of theseconnectors may be difficult, awkward, and frustrating. Also, theconnectors must be loosened or removed in order to disassemble thewheelchair for transport in cars.

Further, the tubular frame and the various connectors make conventionalwheelchairs difficult to "grow" to accommodate the physical growth ofthe user. For example, side frames often limit the size of the seat thatcan be secured to the wheelchair. This presents problems for a child.Changing the size of the seat may require removal and replacement offrame tubes at a manufacturing facility or authorized dealer, whichinvolves re-specification and manufacture of parts, and labor and timeto re-work the wheelchair. If a larger seat, and therefore a widerframe, is initially used in a pediatric wheelchair, it may be necessaryto position abductors and other support pads laterally inwardly of thesides of the frame. However, a child would have difficulty reachingoutwardly to the drive wheels.

Disabled persons who look to wheelchairs for mobility also are dependenton the wheelchair for bodily support. It is important that thewheelchair be lightweight and easily maneuverable, in order to conservethe energy of the person. Also, the seat and back should be easilyadjustable to provide proper posture and comfort. Improper seating isnot only uncomfortable but may create additional physical problems forthe person using the chair. The width, height, depth, and tilt of theseat as well as the width, height, and tilt angle of the back of theseat, affect proper seating. Proper adjustments of the seatingvariables, together with proper sizing of the wheelchair contributes toa more neutral skeletal alignment and may impede the progression ofskeletal deformities and muscle contracture, better manage seatingpressures and reducing the potential for pressure sores, improve theseating stability of the occupant, increase sitting tolerance throughincreased comfort, and decrease fatigue. The tubular frame however ofteninterferes with attachment and adjustment of the pads and abductorswhich may be critical to properly supporting the user in the wheelchair.

Accordingly, there is a need in the art for improved wheelchairs thatare readily assembled, disassembled, adjusted, and used for and bydisabled persons. It is to such that the present invention is directed.

SUMMARY OF THE INVENTION

The present invention provides an improved wheelchair having a lowerchassis, a chassis back, and an upper chassis defined by flat platesurfaces. The lower and the upper chassis each have a pair of elongatedsubstantially parallel arms that extend from respective land portions ofthe chassis away from the chassis back. The arms connect to casterwheels at distal portions thereof. A seat attaches to the chassis forsupporting a person in the wheelchair. A pair of push handles attach tothe chassis back. A pair of drive wheels attach to the chassis formoving the wheelchair. Axle mounts for the drive wheels readily attachto the chassis back which facilitates adjustments to the track, camber,height, and size of the wheels. The seat support readily attaches to theflat surfaces and permits easier adjustments to the seat angle, the seatposition relative the axles of the wheels, and the seat back angle.Assembly and disassembly of the component parts is facilitated, not onlyfor transporting the wheelchair, but for installing larger components toaccommodate growth of the user.

The present invention further provides improved components forwheelchairs. A seat support according to the present invention providesadjustable orientation as to seat angle, height, and position relativethe axles of the drive wheels. The seat support comprises a pair oftubular frame columns for rigidly connecting in a spaced-apartrelationship to a chassis of a wheelchair. Opposing sides of each of theframe columns define a plurality of pairs of aligned openings spacedapart in the frame columns between an upper portion of the frame columnsand a lower portion. A pair of support pins extend between the pair offrame columns through one of the aligned pairs of openings, for settingthe height of a seat in the wheelchair. A pair of seat columns areslidably received within the frame columns with the lower ends supportedon the support pins and the upper ends defining a pair of spaced-apartopenings. A pair of seat connectors are received within the seatcolumns. The seat connectors each have an upper surface that receives aseat means for the use of the wheelchair. A depending pivot mountdefines a pivot bore at one side and an arcuate member defines aplurality of angle bores at an opposite side. Bolts extend through theopenings in the upper ends of the seat columns and through the pivotbore and a selected one of the angle bores, for disposing the seatconnector at angle relative to the seat support columns. Seat meansrigidly connects to the seat connector for being disposed at a selectedangle. In a preferred embodiment, a seat frame attaches to the seatconnector and includes elongated slots for selective positioning of theseat in the wheelchair.

The invention provides an axle mount for attaching a quick-release wheelto a wheelchair. The axle mount comprises a split-sided cylinder havinga pair of spaced-apart flanges that extend laterally from the edges ofthe split in the cylinder. The flanges define bores for receivingfasteners to clinch the split-sided cylinder together, whereby an axlesleeve received in the cylinder is rigidly secured therein. A mountingflange extends outwardly of the split-sided cylinder and defines atleast one bore therethrough for receiving a fastener for securing theaxle mount to a wheelchair chassis. In a preferred embodiment, themounting flange defines a longitudinal slot disposed at an acute angleto the cylinder for receiving a nut and defines a plurality ofspaced-apart bores along the slot. The axle mount, being attached to awheelchair chassis and pivoted on one of the bores in the spaced-apartflanges, is selectively disposed at an angle on the chassis for settingthe camber of a wheel attached to the axle sleeve.

The invention provides a caster block that attaches to a frame of awheelchair for receiving a caster wheel. The caster block comprises ahousing having a central bore and a plurality of spaced-apart channelsfor receiving bolts for attaching the housing to a frame of awheelchair. A resilient core is received in the central bore and definesan axial bore for receiving a shaft of a caster wheel. The distal endsof the core define recesses which receive bearing races. The casterwheel is rotatably engaged to the caster block by extending the shaft ofthe caster wheel through the bore of the core and securing the shaftwith a nut. In a preferred embodiment, the housing defines at least onechannel therethrough which receives a pin having an annular flangeextending outwardly in a lower portion. A spring is received on the pinand seated against the flange. A cam lever pivotally connects to an endof the pin. The cam lever, being moved from a first position to a secondposition, moves the pin within the channel from a recessed positionwithin the housing to an extended position with a portion of the pinextending outwardly of the housing, for engaging a slot in a flange of acaster wheel to lock the wheel in a fixed position.

The present invention provides a wheel lock that attaches to a framemember of a wheelchair for restraining a wheel on the wheelchair fromrotation. The wheel lock comprises a bottom plate that has an flangethat defines an arcuate cavity on a side edge and a mounting block on anopposing side. The flange and the mounting block extend outwardly in afirst direction from the plate to define a recess. The block defines afirst tapped bore in an upper surface and a pair of bores in a sidesurface. A top plate has an edge that matingly engages the arcuatecavity of the top plate and defines a bore that aligns with the tappedbore for receiving a fastener for securing the top plate to the bottomplate and sandwiching the frame member in the recess between the top andthe bottom plates. A handle pivotally attaches to one of the bores inthe side surface. A lock arm pivotally attaches to the other of thebores in the side surface and is pivotally engaged to an end of thehandle. A rigid pin extending laterally from an end of the lock arm. Thehandle moves between a first position and a second position in order tomove the rigid pin from an engaged position against a wheel of awheelchair to a disengaged position spaced apart from the wheel.

Objects, features, and advantages of the present invention will becomeapparent from a reading of the following specification, in conjunctionwith the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded view of a preferred embodiment of awheelchair according to the present invention.

FIG. 2 is a plan view of a metal sheet for forming the chassis of thewheelchair illustrated in FIG. 1.

FIG. 3 is a detailed perspective exploded view of a seat support thatpermits positional adjustment of the seat that mounts to the chassisillustrated in FIG. 2.

FIG. 4 is a detailed perspective view of the latch and handle for theseat support illustrated in FIG. 3.

FIG. 5 is a perspective back view of the wheelchair illustrated in FIG.1.

FIG. 6 is a plan view of an axle mount for the wheels of the wheelchairillustrated in FIG. 1.

FIG. 7 is a cut-away perspective view detailing the axle mount and seatsupport for the wheelchair illustrated in FIG. 1.

FIG. 8 is a exploded perspective view of the caster block for thewheelchair illustrated in FIG. 1.

FIG. 9 is a perspective view of the wheel lock for the wheelchairillustrated in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now in more detail to the drawings, in which like numeralsindicate like parts throughout the several views, FIG. 1 shows aperspective view of a preferred embodiment of a wheelchair 10 accordingto the present invention in which subassemblies (a) for rolling movementof the wheelchair, (b) for seating and orientation adjustments, and (c)for pushing and directing the wheelchair, readily attach to a chassis 12having attaching surfaces defined by flat plates. The rolling movementsubassembly includes drive wheels 16 that are mounted in axle mounts 15which are track, camber and height adjustable. The seat subassemblygenerally designated 18 includes a seat frame 120 and an adjustable seatback generally designated 17. Push handles 26 connect to the chassis 12and to the seat back for pushing and directing the wheelchair. Thesesubassemblies are discussed in detail below.

The chassis 12

FIG. 2 illustrates in plan view a flat plate 34 that folds along foldlines 36 to define the chassis 12. The plate 34 defines a lower chassis38, an upper chassis 40, and a chassis back 42, separated by therespective fold lines 36. The lower chassis 38 includes a land portion44 and the upper chassis 40 includes a land portion 46. The lowerchassis 38 and the upper chassis 40 each include a pair of elongatedsubstantially parallel arms 48 that extend from the respective landportions 44 and 46. The arms 48 define openings 45, 47, and 50 in distalends thereof for connecting caster blocks 51 (see FIG. 1) and casterwheels 14 to the chassis 12, as discussed below.

The land portion 44 in the lower chassis 38 defines two pairs ofopenings 49, an opening 52, and a plurality of openings 53 on laterallyopposing sides, for purposes discussed below. The opening 52 reduces theweight of the chassis 12 and provides an access port into the interiorof the chassis for assembly and disassembly of the wheelchair 10. Theopenings 53 receive bolts for connecting axle mounts for strollerwheels. The land portion 46 in the upper chassis 38 defines an opening54 with notches 54a, for receiving the seat support 18 as discussedbelow. The plate 34 is preferably a sheet of 0.125 inch stainless steel.In an alternate embodiment, the chassis 12 is molded or cast to shapeusing a high strength polymer, plastic material, or metal.

The chassis back 42 defines three sets of aligned pairs of openings 56,57, and 58 for receiving bolts that attach the axle mount 15 to thechassis back 42. Each set of opening 56, 57, and 58 are symmetricallydisposed relative to a longitudinal axis of the chassis 12 indicated byphantom line 55. In the illustrated embodiment, a central portion of thechassis back 42 includes four sets of the symmetrically aligned pairs ofopenings 56 which are spaced apart between the lower chassis 38 and theupper chassis 40. As discussed below, the openings 56 cooperate with theaxle mount 15 to define the camber of the drive wheels 16. Five openings56a, 56b, 56c, 56d, and 56e are provided in each set on the two sides ofthe chassis 12. The five openings 56a, 56b, 56c, 56d, and 56e correspondto 12°, 9°, 6°, 3°, and 0° of camber, respectively. Fourvertically-spaced sets of the openings 56 are provided to accommodatedifferent sizes of wheels 16 without affecting the height of thewheelchair seat relative the rolling surface on which the wheelchairmoves.

The laterally outer portions of the chassis back 42 each define thesecond set of spaced-apart openings 57. Four openings 57 are provided inspaced-apart relation in correspondence with the spacing for the foursets of openings 56. The openings 57 are used in association with a boltand nut for securing the axle mount 15 to the chassis back 42, asdiscussed below. The particular opening 57a, 57b, 57c, and 57d usedcorresponds to the selected wheel size opening 56. Also, the openings 57may be used for attaching the lower push handle mounts to the chassisback 42, as discussed below.

The third set of openings 58 are defined in the chassis back between thecentral portion and the lateral outer portions. The openings 58 providea pivot point for the axle mount 15, as discussed below. The openings56, 57, and 58 accordingly facilitate connecting the axle supports 15for the wheels 16, so that the track, the camber, and the height of thedrive wheels 16 can be adjusted, as discussed below.

In the illustrated embodiment, a fourth set of symmetrically alignedpairs of openings 59 are used for connecting the supports for the lowerends of the push handles 26, as discussed below.

The seat support 18

FIG. 3 is a detailed perspective and partially exploded view of the seatsupport 18 which connects to the land portions 44 and 46 in the lowerand upper chassis 38 and 40. The seat support of the present inventionpermits independent adjusting of the seat angle, the seat height, andthe seat position relative a longitudinal axis of the wheelchair 10. Theseat support 18 comprises a pair of tubular frame columns 60 thatrigidly connect to the chassis 12 in a spaced-apart relationship to thelower chassis 38 and the upper chassis 40. The shape of the opening 54corresponds to the cross-sectional shape of the frame columns 60. Theframe columns 60 define openings 61 for receiving bolts 63a for securingthe columns to the chassis 12 with nuts 63b. The bolts 63a pass throughthe openings 49 in the lower chassis 38 and the notches 54a in the upperchassis 40 for connecting the frame columns 60 to the chassis 12. Aflange 65 extends laterally from an inner one of the sides 62 forsupport. The opposing sides 62 of the frame columns 60 define aplurality of pairs of aligned openings 64 which are verticallyspaced-apart between an upper portion 68 of the framed columns 60 and alower portion 70. A pair of support pins 72 slidably extend between thepair of frame columns 60 through a selected one of the aligned pairs ofopenings 64.

The support pins 72 engage and support a latch handle 74 which isdisposed between the frame columns 60. As best illustrated in FIG. 4,the latch handle 74 has a front grip 76 and a pair of upwardly extendingsides 78. A pair of hook-like ears 82 and 84 extend upwardly atrespective distal end portions of the sides 78. An upper edge of theside 78 defines a recess 86 adjacent the ear 84, for purposes discussedbelow. Each side 78 defines a longitudinal slot 80 through which thepins 72 pass. A recess 81 is defined in a lower edge of the slot 80 nearthe ear 84. The handle 74 can move longitudinally relative the chassis12 away from and towards the chassis back 42. A spring 88 connectsbetween one of the pins 72 and the handle 74 for biasing the handle to alocked position towards the chassis back 42. The flanges 65 facilitatealigning the handle 74 between the frame columns 60.

Returning to FIG. 3, a pair of seat columns 94 are slidably receivedwithin the frame columns 60. The lower ends 96 of the seat supportcolumns 94 are supported on the pins 72 which are received in notches95. In an alternate embodiment, a plate is slidingly received within theframe column 60 for being supported directly on the support pins 72. Theplate is preferably made of steel, while the seat column 94 and theframe column 60 are preferably aluminum extrusions. The seat column 94and the frame column 60 can be molded using a high strength polymer orcomposite material, a plastic, or metal.

The height of a cushioned seat (not illustrated) connected to the seatsupport 18 accordingly can be adjusted by positioning the support pins72 in a selected one of the pairs of aligned openings 64 in order to setselectively the height of the seat columns 94 relative to the chassis12. A pair of elongate members 97 rigidly connect between the lower endsof the seat columns 94. An upper end 98 of each seat support column 94defines a pair of spaced apart openings 100 and 101, for a purposediscussed below.

Seat connectors 102 insert into the seat columns 94. The seat connectors102 have an elongate member 103 with an upper surface 104 and a pair ofspaced-apart bores 106 defined in the distal portions. An integral anglemount 110 and pivot mount 112 depend from the member 103. The pivotmount defines a pivot bore at one side and the angle mount 110 defines aplurality of angle bores 116 disposed in the arcuate member at anopposite side. Bolts 118 extend through the openings 100, 101 andthrough the pivot bore 112 and a selected one of the angle bores 116,for disposing the seat connectors 102 at an angle relative to the seatsupport columns 94.

With reference to FIGS. 1 and 3, a seat frame 120 attaches to the seatconnectors 102 for holding a conventional cushioned seat for thewheelchair 12. The seat frame 120 in cross-sectional view issubstantially J-shaped as defined by a bottom 122, a side 124, and anupper member 126 that extends over a portion of the bottom. A pair ofears 128 extend upwardly from opposing sides of the upper member 126. Alug 129 extends outwardly of each ear 128, for a purpose discussedbelow. In the illustrated embodiment, the lugs 129 are defined by boltsextending through bores in the ears 128, with nylon cylinders receivedon the bolts outwardly of the ears. In an alternate embodiment (notillustrated), hook latches pivotally connect to the ears 128 forsecuring the seat back 17 to the seat frame 120. The seat frame 120 ispreferably formed from a sheet of 0.125 inch stainless steel, and foldedto define the side 124 between the bottom 122 and the upper member 126with its ears 128.

The bottom 122 defines aligned pairs of elongated slots 130 on opposingsides for engaging the seat frame 120 to the seat connectors 102. Bolts131 extend through the slots 130 and the bores 106 and engage nuts forsecuring the seat frame 120 to the seat connectors 102. The bottom 122also defines aligned pairs of elongated slots 132 on opposing sides,spaced outwardly of the slots 130, for engaging a conventional cushionedseat (not illustrated) to the seat frame. Conventional seats comprise awood base, foam padding, and upholstery. The cushioned seat rigidlyconnects to the seat frame 120 with a plurality of threaded fastenersthat extend upwardly through the slots 132 and engage T-nuts attached ona lower surface of the wood base of the seat, to lock the seat to theseat frame. Foot rests and arm rests (not illustrated) conventionallyattach to the wood base of the cushioned seat using T-nuts andfasteners.

The seat back 17

With reference to FIGS. 1 and 5, the seat back 17 pivotally connects tothe seat frame 120 and to brackets 140 on the push handles 26. The seatback 17 includes a back frame 142 from which pivot tabs 144 extendrearwardly on opposing sides. The pivot tabs 144 each define a generallyU-shaped slot 146 for engaging the lugs 129 on the ears 128 and therebypivotally engaging the seat back 17 to the seat frame 120. A pair ofarcuate pivot arms 148 extend rearwardly at an upper end of the seatback 17. Each arm 148 defines an arcuate slot 150 through which athreaded fastener extends for engaging the arm to the bracket 140 on therespective push handle 26. In an alternate embodiment (not illustrated),the slot 150 defines a series of steps to restrict inadvertent movementof the seat back should the securing fasteners loosen. Connecting thearms 148 to the brackets 140 secures the seat back 17 in a selectedposition at an angle relative the seat frame 120. In the illustratedembodiment, the back frame 142 defines an opening 141 which reduces theweight of the wheelchair. A conventional cushioned seat back (notillustrated) attaches to the back frame 142 by threaded fasteners thatslidingly extend through longitudinal slots 143 and engage T-nuts fixedto the cushioned seat back. In the illustrated embodiment, the seat back17 is made from a steel plate and folded to define the pivot tabs 144and the pivot arms 148.

As best illustrated in FIG. 5, the brackets 140 are extruded membersdefining a split-side cylinder 152 for slidingly receiving a push handle26. Flanges 154 extend laterally of the edge of the split in thecylinder 152. A pair of threaded bores 156 in the bracket 140 receivebolts for tightening the split cylinder 152 against the push handle 26and thereby securing the bracket in place on the push handle. Thebracket 140 includes a flange 158 having an elongated slot 160. A boltpasses through the slot 160 and the slot 150 in the arm 148 to securethe seat back 17 to the bracket 140 in the selected angled positionrelative the seat frame 120.

The push handles 26

FIG. 5 is a back perspective view of the wheelchair 10 and particularlyillustrates the connection of the push handles 26 to the wheelchair tothe chassis 12. The push handles 26 are elongated tubes having a handgrip 184 defined at an upper end 185 and a lower end 180 that isslidingly received in a bracket 182 attached to the chassis back 42. Thebracket 182 is structurally similar to the bracket 140, which arepreferably formed as extrusions. The bracket 182 has a split-sidecylinder 186 for receiving the lower ends 180 of the push handles 26.Flanges 188 extend laterally of the split-side cylinder 186. The flanges188 define a pair of threaded bores 190 and 192. Bolts are connected tothe bores 190 and 192. A hook latch 194 pivotally mounts between theedges of the split-side cylinder 186 to the bolt in the bore 190. Thelatch 194 is biased inwardly by a spring. The latch 194 engages a slit181 in the lower end of the push handle 26 and thereby engages the pushhandle in the bracket 182. A flange 196 extending laterally of thecylinder 186 includes two bores 198 for receiving bolts that extendthrough holes in the chassis back 42 for securing the bracket 182 to thechassis 12. Although not illustrated, conventional anti-tip tubes insertinto a lower opening of the cylinder 186 and are secured in place by abolt extending through a bore 200.

The drive wheels 16

FIG. 6 is a plan view of the axle mount 15 for connecting the drivewheels 16 to the chassis 12. The axle mount 15, also preferably anextrusion, comprises a split-side cylinder 210 having spaced apartflanges 212 extending laterally from the split. A bore 214 extendsthrough the flanges 212 to define a pivot point for the axle mount 15,as discussed below. A tapped bore 216 is formed in an outer portion ofthe axle mount 15. An arcuate slot 218 is defined in a flange surfaceopposite the flange 212 and receives a bolt therethrough for pinchinglysecuring the axle mount 15 to the chassis back 42. A flange surface 220extends laterally from the split-side cylinder 210. An elongated slot222 is defined in the surface of the flange 220. The slot extends from adistal edge 224 at an angle towards the cylinder 210. The slot 222 issized for slidingly receiving a nut to engage a bolt as discussed below.A plurality of openings 226 are spaced apart in the slot 222. Thespacing between the adjacent openings 226 corresponds to the spacing ofthe openings 56 in the chassis back 42. These openings 226 and 56cooperate to define the camber of the wheels 16. A bolt extends througha selected one of the openings 56 and its corresponding opening 226 inthe axle mount 15 and engages the nut in the slot 222, in order to setthe camber of the drive wheels. In an alternate embodiment, the openings226 are tapped for engaging the bolt, thereby avoiding the need tomachine the slot 222 and to use the nut.

The split-side cylinder 210 receives a conventional tubular axle sleevethat receives a quick-release pin for holding quick-release wheels,which are conventional in the art. The threaded bore 216 receives abolt, and cooperates with the opening 214 and the bolt therethrough totightly bring the split-sides of the cylinder 210 together in order toclinch and secure the quick-release axle sleeve within the cylinder.

The caster blocks 51

With reference to FIGS. 1 and 8, the caster blocks 51 receive the casterwheels 14 for rolling movement of the wheelchair 12. The caster blocks51 have an extruded housing 230 which defines a cylindrical central bore232 therethrough with a plurality of channels 233 for receiving bolts(not illustrated) that pass through the openings 47 for securing thecaster blocks to the distal ends of the arms 48. A resilient core 234 isreceived in the bore 232. The core 234 is preferably molded withpolyurethane. The core 234 defines a cylindrical bore 236 therethroughand the distal ends include countersunk recesses 238 for receivingbearing races 240. A plate washer 242 covers the bearing race 240. Ashaft 244 of the caster wheel 14 extends through the bore 236 andengages a nut 246 for securing the caster wheel in the caster block 51.

The illustrated embodiment of the present invention provides a casterwheel lock that selectively restricts rotation of the castor wheel 14.The housing 230 defines a pair of channels 250 for receiving a pin 251.A flange 252 extends outwardly near a lower end of the pin 251 to definea seat for a spring 253. A lug 254 projects upwardly from the pin 251and through the opening 45 in the arm 48. A lower surface of the arm 48on the upper chassis 40 acts as a stop for the upper end of the spring253. A cam lever 255 pivotally connects with a pin 256 to the lug 254. Atip 257 of the pin 251 extends through the opening 45 in the arm 48 onthe lower chassis 38 for selective engagement with a slot 258 in acircular flange of the caster wheel 14. The illustrated embodiment ofthe caster block 51 provides a pair of the channels 250 so that a singleextrusion can be used for both the right and left arms 48. The openings45 are off-center so as to provide a sufficient surface for theoperation of the cam lever 255.

The wheel lock

With reference to FIGS. 1 and 9, the wheelchair includes a pair of wheellocks 259 to hold the wheels 16 from easily rotating. The wheel lock 259comprises a bottom plate 260 and a top plate 262 which sandwich an arm48 in a recess between the plates, as best illustrated in FIG. 9. Thebottom plate 262 has a mounting block 266 on one side and on theopposite side has a channel 268 that is defined by a flange 270. Themounting block 266 and the flange 270 extend outwardly from the bottomplate on one side to define a recess therebetween for receiving the arm48. The mounting block 266 defines a tapped bore 272 that extends fromthe upper surface and a pair of tapped bores 274 and 275 on the side.The top plate 262 defines an opening 276 that aligns with the tappedbore 272 in the mounting block 266. The top plate 262 defines on theopposite side an arcuate edge 278 that matingly engages the channel 268.A bolt extends through the opening 276 and engages the bore 272 tosecure the top plate 262 and the bottom plate 260 together around thearm 48.

A pivotable handle 280 attaches to the side of the mounting block 266and pivots at a pin 282 that connects to the bore 274. A link pin 284connects the handle 280 to an arm 286 that pivotally connects with a pin288 to the bore 275 in the mounting block 266. A serrated dowel pin 290extends outwardly at a distal end of the arm 286.

Operation of the wheelchair

The wheelchair 10 of the present invention provides mobility fordisabled persons, while being readily assembled, disassembled, oradjusted to accommodate the needs of the user. The wheelchair 10 isreadily disassembled for transportation in a car. With reference toFIGS. 1 and 5, the guide handles 26 are removed by releasing the latches194 from engagement in the slits 181 of the handles 26. In a preferredembodiment the lower ends of the latches 194 are connected together by aflexible cord (not illustrated). Pulling the cord downwardly causes thelatches 194 to pivot towards each other and outwardly of the slits 181.The handles 26 are then grasped and pulled upwardly, thereby detachingthe lower ends from the bracket 186 while the seat back 17 detaches frompivotal engagement with the lugs 129.

The seat and seat frame 120 may then be removed. With reference to FIGS.1 and 4, the handle 74 is moved from its locked position to the releaseposition by pulling the grip 76 outwardly towards the caster wheels 14and upwardly away from the rolling surface. The members 97 are therebyremoved from engagement with the ears 82 and 84, and the member 97aslips into the notch recesses 86 in the sides 78. The pin 72a slips intothe recesses 81 in the slots 80, and this holds the handle 74 in therelease position. The members 97 are thereafter clear of interferencefrom the ears 82 and 84. The seat frame 120 is grasped and pulledupwardly. The seat columns 94 slidably exit the frame columns 60.

With the seat columns 94 (and seat) removed from the frame columns 60,the height of the seat columns in the wheelchair 12 can be adjusted.With reference to FIG. 3, the pins 72 are selectively inserted into oneof the aligned pairs of openings 64 in order to position the seatcolumns 94 higher or lower in the wheelchair 12 (and thereby adjust theheight of the seat connected to the seat frame 120 on the seat columnsand thereby resulting in a change in the seat height relative to therolling surface on which the wheelchair 10 travels). This isaccomplished by first detaching the spring 88 from engagement with thehandle 74. The pins 72 are removed from the frame columns 60 andre-inserted into one of the aligned pairs of openings 64 at the selectedheight. The pins 72 extend through the slots 80 of the handle 74 inorder to support the handle between the frame columns 60. The spring 88is re-attached for biasing the handle 74 into the locked position.

With reference to FIGS. 1 and 4, the seat frame 120 can be re-installedin the wheelchair 12. The seat columns 94 are aligned with the framecolumns 60 and lowered telescopically into the frame columns. The member97a bears on the notch 86 and pushes the handle 74 downwardly. Thespring 88 causes the handle to retract to the locked position. The ears82 and 84 engage and lock the members 97. The handle 74 moves relativeto the pins 72 in the slot 80 to the locked position. It is noted thatfor front wheel drive, the seat frame 120 can be rotated 180° and thenthe seat columns 94 can be inserted into the frame columns 60.

The subassembly supporting the cushioned seat also provides independentadjustment of the angle of the seat, of the position of the seatrelative to the seat back 17, and of the position of the seat frame 120relative the drive wheel 16. With reference to FIG. 3, the seat angle isadjusted by removing the bolt 118b from engagement with the one of theangle bores 116 in the seat connector 102. The seat frame is pivotedabout the bolt 118a that extends through the pivot bore 112. When theseat frame 120 is positioned at the selected angle, the bolt 118b isre-inserted through the opening 101 and the selected one of the anglebores 116. In the illustrated embodiment, the pivot bores 116 provide arange of seat angles between -5° and 47.5°, at 7.5° increments.

With reference to FIG. 1, the position of the cushioned seat (notillustrated) on the seat frame 120 is adjustable relative to the seatback 17. This accommodates the growth of the person using the wheelchair12. The cushioned seat connects conventionally with fasteners passingthrough the slots 132 in the seat frame 120. In order to adjust thelongitudinally position of the seat relative the seat back 17, thefasteners are loosened and the seat slidably moved with the fastenersmoving along the slots 132. When the seat cushion is in its selectedlocation, the fasteners are tightened to re-secure the seat to the seatframe 120.

The seat frame 120 is longitudinally positionable relative to thechassis back 42. The fasteners extending through the slots 130 and thebores 106 in the seat connector 102 are loosened. The bolts connectingthe arcuate arms 148 to the brackets 140 are likewise loosened. The seatframe 120 is then slidably moved relative the seat connector 102. Thefasteners travel in the slots 130. The seat back 17 pivots as the seatframe 120 is moved longitudinally. The seat back 17 thereby freely movesrelative the brackets 140 as the connecting bolts slide along thearcuate slots 150. When the seat frame 120 is in its selected position,the fasteners and bolts are re-tightened to secure the seat frame 120 tothe seat connector 102. The fasteners connecting the arms 148 of theseat back 17 to the brackets 140 are tightened to secure the seat backin an angled position relative the seat. By adjusting the position ofthe seat frame, the balance of the wheel chair is changed. This alsochanges the position of the shoulder of the user relative to thewheelchair, which is important in enabling the user to propel thewheelchair to the best of the user's ability.

The angle of the seat back 17 is independently adjustable. The bolts 162connecting the arcuate arms 148 to the brackets 140 are loosened. Theseat back pivots at its engagement of the U-shaped slot 146 with thelugs 129. When the seat back 17 is positioned to a selected angle, thebolts 162 are tightened to secure the seat back. A cushioned seat back(not illustrated) connects to the back frame 142 and is selectivelypositioned on the back frame by sliding the fasteners along the slots143.

The track of the drive wheels 16 is also adjustable, for accomodatingdifferent sizes of seats and backs and for facilitating adjusting thewheelchair 12 for the particular user. With reference to FIGS. 1, 2 and6, the track between the wheels 16 is adjusted by loosening the bolts inthe bores 214 and 216. The split cylinder 210 opens slightly allowingthe quick-release axle sleeve to slide longitudinally relative thecylinder until reaching a selected track between the wheels 16. Thebolts in the bores 214 and 216 are tightened to clamp the axle sleevewithin the cylinder 210.

The camber of the wheels 16 is adjustable independently and discussedbelow with reference to FIGS. 2, 6 and 7. The axle mounts 15 attach tothe chassis back 42 at three points. First, a bolt extends through oneof the openings 58, depending on the selected height for the wheels 16for the wheelchair 12, through the open pivot bore 214, and into secureengagement with a nut. Second, a nut (not illustrated) is placed in thechannel 222. A bolt is selectively inserted through one of the openings56 and through the aligned one of the openings 226 depending upon thedesired angle of camber for the wheel 16. For example, the bolt isinserted through hole 56a for a 12° of camber. The openings 56a, b, c,d, and e provide 12, 9, 6, 3, and 0 degrees of camber, respectively.Third, a bolt extends through one of the openings 57, through the slot218, and into engagement with a nut. The bolts are tightened to securethe axle mount 15 to the chassis back 42.

The camber is adjusted by loosening the bolts in the pivot bore 214 andthe slot 218. The bolt in the opening 226 is removed. The nut in thechannel 222 is moved to the selected camber opening 226a, b, c, d, or e.The bolt is re-inserted through the selected camber opening 56, andengaged to the nut in the channel 222. The bolts in the bores 58, 214,the bore 57 and the slot 218, and the bores 56, 226 are tightened tosecure the axle mount 15 at the selected camber.

The wheelchair 12 according to the present invention accommodates growthof the person who must rely on such for mobility. The wheelchair 12 isreadily configured for use with stroller wheels using an axle mount 15that does not include the flange 220. The openings 53 in the lowerchassis 38 align with the bore 214, the slot 218 and the bore 216 in theaxle mount 15 for attaching the axle mount to the underside of thechassis 12 for receiving an axle from a stroller wheel. Thequick-release axle sleeve is received in the cylinder 210 and locked bysecuring the bolts in the bores 214 and 216. At an appropriate timeafter the child has grown, the stroller wheels are removed and drivewheels 16 added. The axle mount 15 is then moved to the chassis back 42for receiving the quick-release wheel 16, as discussed above.

With reference to FIG. 8, the caster wheels 14 are selectively locked torestrain rotation about the castor block 51. The cam lever 255 isrotated from a first position with a flat 255a bearing on the arm 48 toa second position with a flat 255b bearing against the arm 48. With thecam lever 255 in the first position, the spring 253 bears on the flange252 and pushes the tip 257 of the pin 251 into engagement with the slot258 in the circular flange of the caster wheel 14. As the cam lever 255moves to the second position, the pin 251 is retracted from the slot 258and moves upwardly within the caster block 51. The flats 255a and 255bhold the pin 251 in the engaged and disengaged positions, respectively.

With reference to FIGS. 1 and 9, the wheelchair 10 can be held fromeasily being moved by actuating the wheel lock 259. The handle 280 isgrasped and pushed away from the drive wheel 16. This causes the arm 286to pivot downwardly about the pivot pin 288. The dowel pin 290 therebymoves downwardly and into engagement with the tire on the drive wheel16. The wheel lock 259 is released by pulling the handle 280 towards thedrive wheel 16 and thereby causing the arm 286 to pivot upwardly andbring the dowel pin 290 away from engagement with the drive wheel.

The benefits of the improved wheelchair may be gained with conventionaltubular wheelchairs by attaching flat plates to the tubes of the framefor receiving the subassemblies disclosed herein, although in apreferred embodiment, the wheelchair 10 includes the chassis 12according to the present invention. Manufacturing the frame 12 in astandard size accomodates the many different size combinations of seatsand backs, rather than constructing a specific frame for each differentcombination. In an alternate embodiment, a drive motor attaches to thechassis back 42 and operatively connects to the drive wheels 16 forpropelling the wheelchair 10. It is to be appreciated that the chassis12, the frame columns 60, and the caster blocks 51 may be integrallyformed by casting or molding. Similarly, other of the components for thewheelchair 10, such as the seat back 17, the seat frame 120, and theaxle mounts 15, can be formed by casting or molding.

The specification has thus described in various embodiments thewheelchair of the present invention including the manufacture and usethereof. It is to be understood, however, that numerous changes andvariations may be made in the construction of the present invention. Itshould therefore be understood that modifications to the presentinvention may be made without departing from the scope thereof as setforth in the appended claims.

What is claimed is:
 1. A support for connecting a seat to a chassis of awheelchair, comprising:a pair of tubular frame columns for rigidlyconnecting in a spaced-apart relationship to a chassis of a wheel chair,two opposing sides of each of the frame columns defining a plurality ofpairs of aligned openings spaced apart in the frame columns between anupper portion of the frame columns and a lower portion; a pair ofsupport pins that extend between the pair of frame columns through oneof the aligned pairs of openings; a pair of seat columns slidablyreceived within the frame columns with lower ends supported on thesupport pins and upper ends defining a pair of spaced-apart openings; apair of seat connectors, each having an upper surface that defines apair of spaced-apart bores for receiving a seat frame and a dependingpivot mount that defines a pivot bore at one side and a plurality ofangle bores in an arcuate member at an opposite side; bolts extendingthrough the openings in the upper ends of the seat columns and the pivotbore and a selected one of the angle bores, for disposing the seatconnector at angle relative to the seat support columns; and seat meansrigidly connected to the upper surface of the seat connector, wherebythe seat means for the wheelchair is disposed at an angle.
 2. Thesupport as recited in claim 1, wherein the seat means comprises a seatframe having a bottom which defines at least one spaced-apart pair ofelongated slots for receiving threaded fasteners therethrough forengaging a cushioned seat, the seat frame rigidly connected to the uppersurface of the seat connector.
 3. The support as recited in claim 1,wherein the seat frame further comprises:a pair of ears extendingupwardly on opposing sides of the bottom; and a pivot pin rigidlyconnected to each ear; and further comprising a back support pivotallysupported at a lower end by the pivot pins in the ears with means forrigidly securing an upper end from pivoting after the back support isindependently angled relative the seat.
 4. A seat support for awheelchair, comprising:at least one assembly of a telescopically-joinedsupport column and seat column, the seat column slidably received withinthe support column and the support column for being rigidly connected toa chassis of a wheelchair; support pins disposed in the support columnfor positioning the seat column at a selected position relative to thesupport column; a pair of members extending between opposing lower sideportions of the seat column; a latch plate defining opposing slots inside walls thereof, through which the support pins extend, the latchplate further defining opposing ears in each side wall which ears extendin a first direction therefrom and the ears and the side wall define tworecesses for receiving the members, the latch plate moveable from afirst position detached from the members and a second position with themembers engaged to the latch plate by being received in the recesses;means for detaching the latch plate from engagement with the members forselectively removing the seat column from the support column; seatconnectors pivotally attach to the seat column for moving to a selectedangle relative to the seat column and adapted to engage a seat for thewheelchair; and means for securing the seat connectors at the selectedangle.
 5. The seat support as recited in claim 4, wherein the supportcolumn comprises a pair of tubular frame columns adapted for rigidlyconnecting to the chassis of the wheelchair.
 6. The seat support asrecited in claim 4, wherein the seat column comprises a pair of tubularcolumns that are slidably received by the support column, with a lowerportion thereof seated on the support pins to position the supportcolumn at the selected position relative to the seat column.
 7. The seatsupport as recited in claim 5, further comprising means for releasingthe seat column for being secured at the selected position, whereby theseat column is removable for resetting the position of the seat columnat another selected position.
 8. The seat support as recited in claim 4,wherein each seat connector comprises a first member having a surfacefor receiving the seat and a second arcuate member that defines a pivotbore in a first end portion and a plurality of angle bores spaced-apartin a second end portion, whereby the seat connector, being pinned by thepivot bore to the seat column, pivots relative to the seat column to aselected angle.
 9. The seat support as recited in claim 7, wherein themeans for securing the seat connectors at the selected angle comprises apin removably secured through the seat column and a selected one of thepivot bores.
 10. The seat support as recited in claim 4, wherein theseat comprises:a seat frame adapted for engaging the seat connectors;and a cushioned pad attached to the seat frame.
 11. The seat support asrecited in claim 10, further comprising a seat back pivotally engaged tothe seat frame for selective angling of the seat back relative to theseat frame; and means for securing the seat back in the selectedposition.
 12. The seat support as recited in claim 10, wherein the seatframe further comprises a pair of ears extending in a first direction onopposing sides of the seat frame, the ears each defining a boretherethrough; anda pivot pin extending through a respective bore forpivotally connecting the seat back to the seat frame.
 13. The seatsupport as recited in claim 4, further comprising a spring extendingbetween the latch plate and one of the support pins, whereby the latchplate is biased to the first position.
 14. The seat support as recitedin claim 13, wherein the opposing slots define a first elongate portionfor guiding lateral movement of the latch plate relative to the seatcolumn and a second portion extending in a second direction, whereby thelatch plate is movable in the second direction upon contact by themembers against the side walls in order to move the latch plate from thesecond position to the first position.